Effect of maternal apical periodontitis on the final step of insulin signalling and inflammatory pathway in the adult male offspring of rats

Abstract

Aim: To evaluate the final step of insulin signalling, inflammatory pathway (related to the inhibition of insulin signalling), peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α) protein content and DNA methylation in the Slc2a4 gene promoter region in the skeletal muscle of adult male offspring of rats with apical periodontitis (AP) in a single tooth or in four teeth.

Methodology: Female Wistar rats were distributed into three groups: a control group, a group with one tooth with AP and a group with four teeth with AP. Thirty days after induction of AP, female rats from all groups were mated with healthy male rats. When male offspring reached 75 days of age, the following analyses were performed in the gastrocnemius muscle (GM): insulin-stimulated Akt serine and threonine phosphorylation status; NF-κB p50 and p65 subunits phosphorylation status; GLUT4, TNF-α and PGC-1α protein content by Western blotting; GLUT4 and TNF-α gene expression by real-time polymerase chain reaction (PCR); and DNA methylation in the Slc2a4 gene promoter region by restriction digestion and real-time PCR. Analysis of variance was performed, followed by Tukey's post hoc test. p values <.05 were considered to be statistically significant.

Results: Maternal AP in four teeth decreased insulin-stimulated Akt serine and threonine phosphorylation status, reduced GLUT4 gene expression and its protein content, and increased NF-κB p50 and p65 subunits phosphorylation status in the GM of adult offspring. There were no alterations in the parameters analysed in the GM of adult offspring of rats with AP in a single tooth. In addition, maternal AP did not affect TNF-α gene expression and its protein content, PGC-1α protein content and DNA methylation in the Slc2a4 gene promoter region in the GM of adult offspring.

Conclusions: Maternal AP in four teeth was associated with impairment in the final step of insulin signalling in the GM of adult male offspring in rats. An increase in NF-κB activity may be involved in this decrease in insulin signalling. This study demonstrates the impact of maternal AP on the health of offspring, demonstrating the importance of maintaining adequate maternal oral health to prevent diseases in adult offspring in rats.

Keywords: apical periodontitis; foetal development; glucose transporter type 4; inflammation.